DefaultValueConverter does not work within styles

[viktorspacil]

Describe the bug

I had to newly explicitly register and specify DefaultValueConverter for bindings within styles to automatically convert Methods to ICommand. This is new behavior coming with the vesion 11.1.0-rc1, version 11.0.10 was ok. Minimal sample to simulate this behavior is attached.
TestApp.zip

To Reproduce

1. Start the app
2. Button "Click me" should be clickable but it is not (it is grey out/disabled)

You have to explicitly set the DefaultValueConverter converter on binding for the Command property within button style to get the button working.

Expected behavior

No response

Avalonia version

11.1.0-rc1

OS

No response

Additional context

No response

[grokys]

Thanks @viktorspacil - yep looks like a regression. The reason I couldn't reproduce is that the command is bound in a style - I didn't try that and seems we have no tests for this case.

The source of the problem is that the XAML compiler is producing a call to CompiledBindingPathBuilder.Method in this case instead of a CompiledBindingPathBuilder.Command even though it should be possible to determine that the method is being bound to a command here.

This worked before the binding refactor because the default value converter even in the case of compiled bindings used MethodToCommandConverter however after the binding refactor, MethodToCommandConverter is only used for reflection bindings as it's marked as RequiresUnreferencedCode.

I think the best fix will be to make the XAML compiler recognise that the binding needs to provide an ICommand and call CompiledBindingPathBuilder.Command.